Process of producing combination printing-plates for printing combined half-tone and printed type or line work.



UNITED strirrns PATENT orrion.

GAERL BLECHER, OF BERLIN-BAELEM, GERMANY, ASSIGNOR T0 ROTOPHOT 'AKTIEN- GESELLSCHAFT Fl'l'R GRAPHISCl-IE INDUSTBIE, OF BERLIN, GERMANY.

PROCESS OF PRODUCING CQMBINATIGN ERINTING-PLATES FOR ERINTING' COMBINED .HALF-TOHE AND PREN'IED TYPE CPR LINE WORK.

No Drawing,

To all whom it may concern Be it known that I, CARL Bnnonnn, suhjeot of the King of Prussia, residing at Berlin-Dahlem, Germany, Friedbergstrasse 23,

have invented certain newand useful lmcially to a method for making the diapos1- tives used for this production. In the art of making combinedhalttone and printed type and line-work printing plates diapositive showing the printed type and line work between the pictures is employed, this diapositivc being printed on etching paper; the print is then transferred onto the printing: plate, developed and dried. Thereupon first of all the places carrying the printed type and line work are protected with varnish and the pictures are etched. The var nish is then removed, the pictures are pro tected in their turn against the attack from the etching liquid and the printed type and line work is etched, whereupon the varnish and print are removed from the plate which is now ready for printing on the press.

Owing to the repeated protecting and etching operations required the method described is exceedingly tiresome and there fore expensive. It has been, however, un avoidable, the practice having shown on: the time used for etching, the printed type and line work must be less in all cases than the time for etching thepictures. if one were to etch both the line work and the picture for an equal length of time, in case that the line work came out right, the pictures would appear too weak, while, if the time was right for the pictures, then the line work would come out too strongly and would appear too broad.

According to my invention, in order to avoid etching the printed type-or line work and the pictures separately, the degree ct translucency oi the printed type or line wort elements on the one hand and of the darker shades of the pictures on the other hand, which had never heretofore been taken into account, is determined in such. a

(gamed-mm- Specification of Letters Iatent.

Application filed January 27, 1915. Serial No. (L786.

way that the printed type and line work are less covered (in the photographic sense), than the darker and the darkest parts of the pictures. This method renders it possible to produce, on the printing plate, prints of the line work or printed type and of the pictures which can be etched simultaneously, the etching of the printed type and line work elements starting later than the darker and darkest shades of the pictures, in strict accordance with the greater height of the line work relief resulting from the greater translucency of the lines in the diapositive, as compared with the height of the relief of the dark parts of the pictures, which owing to their lower translucency is considerably less. It is a matter of experience to determine the appropriate difierence of trans lucency of the different kinds of reproduction and it is impossible to lay down definite rules o1 general value regarding the absoor line work and the pictures, this depending to a great extent upon the peculiarities or" the printing (copying) method employed in each case. However there is no need for the colors of the line work and pictures to agree, provided that the covering of the line work elements and the darker and darkest shades of the pictures is tuned so as to make the former less than the latter.

In practising my invention I may proceed for instance as follows: The printed type or line work is printed in blue, that is to say, in a color allowing a great amount of actinic light to pass through, upon a collodionor celluloid film or the like. This print is then placed with the type or lines downward upon the picture diapositive, care being taken that the printed type and line Work are in the right places between the pictures. The film is then fixed upon the diapositive and printed. In the copy taken on the printing plate the relief of the printed type and line work will appear higher than therelief of the darkest parts of the picture.

If the hydrotype process is'used for transferring the printed type and line work onto the plate, the concentration of the coloring difierence between the times of exposure for the different kinds of reproduction will suiiice to produce the desired effect.

I chiim:

1. The hereindescribed improvement in the -method of producing combination printing combined half tone and type ornne WOIK, comprising providing a diapositive of the picture to be reproduced, combining them- With a photographic reproduction of the type or line work that is more translucent than the portions of thedia-positive repre senting the dark parts of the picture, and producing it print of said diapositive and photographic reproduction on a, printing phite.

In testimony whereof I affix my signature in presence of two witnesses.

CAR-L BLECHER. Witnesses:

VVILLY P. H. MARTIN, HENRY Humor. 

